Public Class Form1
    ' zunächst die benötigten API-Deklarationen
    Private Declare Sub mouse_event Lib "user32" ( _
      ByVal dwFlags As Long, _
      ByVal dx As Long, _
      ByVal dy As Long, _
      ByVal cButtons As Long, _
      ByVal dwExtraInfo As Long)
 
    Private Const MOUSEEVENTF_ABSOLUTE = &H8000
    Private Const MOUSEEVENTF_LEFTDOWN = &H2
    Private Const MOUSEEVENTF_LEFTUP = &H4
    Private Const MOUSEEVENTF_MIDDLEDOWN = &H20
    Private Const MOUSEEVENTF_MIDDLEUP = &H40
    Private Const MOUSEEVENTF_MOVE = &H1
    Private Const MOUSEEVENTF_RIGHTDOWN = &H8
    Private Const MOUSEEVENTF_RIGHTUP = &H10
    ' Mausklick simulieren mit optionaler Angabe der
    ' Koordinaten, an welche der Mauszeiger autom.
    ' positioniert werden soll
    Public Sub Mausklick(Optional ByVal Button As  _
      MouseButtons = Windows.Forms.MouseButtons.Left, _
      Optional ByVal XPos As Long = -1, _
      Optional ByVal YPos As Long = -1)
 
        ' Mauszeiger positionieren
        If XPos <> -1 Or YPos <> -1 Then
            mouse_event(MOUSEEVENTF_ABSOLUTE + MOUSEEVENTF_MOVE, _
            XPos / My.Computer.Screen.Bounds.Width * 65535, _
            YPos / My.Computer.Screen.Bounds.Height * 65535, 0, 0)
        End If
 
        ' Mausklick simulieren
        Select Case Button
            ' linke Maustaste
            Case Windows.Forms.MouseButtons.Left
                mouse_event(MOUSEEVENTF_LEFTDOWN, 0, 0, 0, 0)
                mouse_event(MOUSEEVENTF_LEFTUP, 0, 0, 0, 0)
 
                ' mittlere Maustaste
            Case Windows.Forms.MouseButtons.Middle
                mouse_event(MOUSEEVENTF_MIDDLEDOWN, 0, 0, 0, 0)
                mouse_event(MOUSEEVENTF_MIDDLEUP, 0, 0, 0, 0)
 
                ' rechte Maustaste
            Case Windows.Forms.MouseButtons.Right
                mouse_event(MOUSEEVENTF_RIGHTDOWN, 0, 0, 0, 0)
                mouse_event(MOUSEEVENTF_RIGHTUP, 0, 0, 0, 0)
        End Select
    End Sub
End Class